32 BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



In the material which I have had the species has been observed 

 but once, Nero station 990, in 859 fathoms off Guam. This speci- 

 men is here figured. It is rather more extreme in its flattened 

 character than in the figures given by Brady, reminding one some- 

 what of OptJialmidium inconstans. The specimen agrees with both 

 the figure and description given by Brady in that the platelike carina 

 separates the chambers from one another very distinctly. In this 

 character the present species differs from that described here as S. 

 tenuimargo which, although having a carina well developed on the 

 last-formed chambers, does not have the chambers well separated 

 in the body of the test. 



SPIROLOCULINA TENUIMARGO, new species. 

 Plate 5, figs. 2, 3. 



Description. — Test much compressed, planospiral, chambers numer- 

 ous, usually more swollen toward the basal end, inflated, nearly cir- 

 cular in transverse section, the apertural end somewhat produced, 

 surface smooth; periphery of the test with a distinct, rather broad, 

 sharp, platelike carina, in young specimens rather even, but in older 

 ones more or less irregular; chambers closely adjacent to one another, 

 not separated; apertural end with a slightly produced and slightly 

 flaring lip; aperture round. 



Length, slightly less than 1 mm. 



Distribution. — Specimens were obtained from two stations; the 

 type, Cat. No. 9153, U. S. N. M., from Nero 1466, in 234 fathoms off 

 Guam and another lot from Albatross D4967, in 244 fathoms off the 

 coast of Japan. 



This species "while having a marginal carina as in S. acutimargo 

 H. B. Brady, has the chambers closely adjacent to one another and 

 not separated by a flat platelike portion as in that species, the form 

 of the chambers is also very different from those of our species, being 

 differently curved and having the basal portion much swollen, espe- 

 cially in the earlier chambers. 



SPIROLOCULINA TENUISSIMA Reuss. 



Spiroloculina tenuissima Reuss, Sitz. Akad. Wiss. Wien, vol. 55, 1867, p. 71, pi. 



1, fig. 11. 



Spiroloculina tenuis H. B. Brady (not Czjzek) (part), Rep. Voy. Challenger, Zo- 

 ology, vol. 9, 1884, p. 152, pi. 10, figs. 9, 10 (not 7, 8, 11). 



Description. — Test very thin, translucent, elongate, compressed, 

 in front view tapering toward either end, chambers long and narrow, 

 peripheral margin broadly rounded, chambers in transverse section, 

 circular; apertural end produced into an elongate neck, aperture 

 rounded usually without distinct teeth, wall smooth. 



Length, usually less than 0.5 mm. 



